The clinical and economic impact of extended battery longevity of a substernal extravascular implantable cardioverter defibrillator.

INTRODUCTION: The extravascular implantable cardioverter defibrillator (EV ICD) has extended projected battery longevity compared to the subcutaneous implantable cardioverter defibrillator (S-ICD). This study used modeling to characterize the need for generator changes, long-term complications, and overall costs for both the EV ICD and S-ICD in healthcare systems of various countries. METHODS: Battery longevity data were modeled using a Markov model from averages reported in device labeling for the S-ICD and with engineering estimates based on real life usage from EV ICD Pivotal Study patient data to introduce variability. Clinical demographic data were derived from published literature. The primary outcomes were defined as the number of generator replacement surgeries, complications, and total healthcare system costs due to battery depletion over the expected lifetime of patients receiving EV ICD or S-ICD therapy. RESULTS: Average modeled battery longevity was determined to be 7.3 years for the S-ICD versus 11.8 years for the EV ICD. The probability of a complication after a replacement procedure was 1.4%, with an operative mortality rate of 0.02%. The use of EV ICD was associated with 1.4-1.6 fewer replacements on average over an expected patient lifetime as compared to S-ICD and a 24.3%-26.0% reduction in cost. A one-way sensitivity analysis of the model for the US healthcare system found that use of an EV ICD resulted in a reduction in replacement surgeries of greater than 1 (1.1-1.6) along with five-figure cost savings in all scenarios ($18 602-$40 948). CONCLUSION: The longer projected battery life of the EV ICD has the potential to meaningfully reduce long-term morbidity and healthcare resources related to generator changes from the perspective of multiple diverse healthcare systems.

Efficacy and Safety of an Extravascular Implantable Cardioverter-Defibrillator.

BACKGROUND: The extravascular implantable cardioverter-defibrillator (ICD) has a single lead implanted substernally to enable pause-prevention pacing, antitachycardia pacing, and defibrillation energy similar to that of transvenous ICDs. The safety and efficacy of extravascular ICDs are not yet known. METHODS: We conducted a prospective, single-group, nonrandomized, premarket global clinical study involving patients with a class I or IIa indication for an ICD, all of whom received an extravascular ICD system. The primary efficacy end point was successful defibrillation at implantation. The efficacy objective would be met if the lower boundary of the one-sided 97.5% confidence interval for the percentage of patients with successful defibrillation was greater than 88%. The primary safety end point was freedom from major system- or procedure-related complications at 6 months. The safety objective would be met if the lower boundary of the one-sided 97.5% confidence interval for the percentage of patients free from such complications was greater than 79%. RESULTS: A total of 356 patients were enrolled, 316 of whom had an implantation attempt. Among the 302 patients in whom ventricular arrhythmia could be induced and who completed the defibrillation testing protocol, the percentage of patients with successful defibrillation was 98.7% (lower boundary of the one-sided 97.5% confidence interval [CI], 96.6%; P<0.001 for the comparison with the performance goal of 88%); 299 of 316 patients (94.6%) were discharged with a working ICD system. The Kaplan-Meier estimate of the percentage of patients free from major system- or procedure-related complications at 6 months was 92.6% (lower boundary of the one-sided 97.5% CI, 89.0%; P<0.001 for the comparison with the performance goal of 79%). No major intraprocedural complications were reported. At 6 months, 25 major complications were observed, in 23 of 316 patients (7.3%). The success rate of antitachycardia pacing, as assessed with generalized estimating equations, was 50.8% (95% CI, 23.3 to 77.8). A total of 29 patients received 118 inappropriate shocks for 81 arrhythmic episodes. Eight systems were explanted without extravascular ICD replacement over the 10.6-month mean follow-up period. CONCLUSIONS: In this prospective global study, we found that extravascular ICDs were implanted safely and were able to detect and terminate induced ventricular arrhythmias at the time of implantation. (Funded by Medtronic; ClinicalTrials.gov number, NCT04060680.).

Contribution of Cardiac Implantable Electronic Devices to Thrombus Formation in Patients With Chronic Thromboembolic Pulmonary Hypertension.

OBJECTIVES: This study aimed to identify the prevalence of cardiac implantable electronic devices (CIEDs) in patients with chronic thromboembolic pulmonary hypertension (CTEPH) and to describe the associated disease burden. BACKGROUND: CTEPH is a debilitating disease, now potentially curable with pulmonary thromboendarterectomy (PTE). The contribution of CIEDs to thrombosis in this patient population has not been previously studied. METHODS: The charts of 982 CTEPH patients, who underwent PTE between January 1, 2009, and December 31, 2015 at University of California-San Diego (UCSD) Medical Center, were reviewed for pacemakers or implantable cardioverter defibrillators (ICDs) implanted before surgery. RESULTS: Among 982 CTEPH patients who underwent PTE, 14 had pacemakers and 3 had ICDs, giving 17 CIEDs and a prevalence of 1.7%. Of these 17 CIEDs, 6 devices were extracted intraoperatively, and 5 of 6 devices were replaced with epicardial leads. Furthermore, of the 950 patients classified by intraoperative UCSD level, 12 of 17 (70.6%) patients with CIEDs had distal disease versus 241 of 933 (25.8%) patients without CIEDs (p = 0.0002). The prevalence of known venous thromboembolism (VTE) was 50% in CIED patients compared with 78.6% in patients without CIEDs (p = 0.018). CONCLUSIONS: At 1.7%, the prevalence of CIEDs in the PTE population was higher than previously reported values, which estimated CIED prevalence between 0.16% and 0.47% in the general population. Moreover, CTEPH patients with CIEDs were more strongly associated with distal disease burden and less likely to have had previous VTE, which suggested that CIEDs may be a nidus for small clots that embolize distally in the pulmonary vasculature.

Clinical Outcomes of Cardiac Resynchronization with Epicardial Left Ventricular Lead.

BACKGROUND: Left ventricular (LV) pacing in cardiac resynchronization therapy (CRT) can be achieved via a transvenous or epicardial route. A surgically implanted epicardial LV (eLV) lead is used after a standard transvenous LV (tLV) lead implantation has failed. However, studies of clinical outcomes in patients with eLV leads and comparisons of outcome between tLV and eLV-CRT are sparse. Therefore, the purpose of this study is to compare clinical response between tLV-CRT and eLV-CRT, as well as to understand the differences within the eLV-CRT population. METHODS: Forty-four patients received eLV-CRT following unsuccessful attempts of tLV-CRT implantation between 2002 and 2013 at the University of California, San Diego (UCSD) and Mayo Clinics. These patients were matched for age, gender, and etiology of cardiomyopathy in a 1:2 ratio with a cohort of patients who received tLV-CRT during the same time period. RESULTS: During a mean follow-up of 57 months, similar clinical outcomes and survival rate were noted between tLV and eLV-CRT patients (all P > 0.05). Within the eLV-CRT group, dilated cardiomyopathy patients had significant improvement in New York Heart Association class and ejection fraction (both P < 0.05), while ischemic cardiomyopathy patients did not (both P > 0.05). eLV-CRT patients with nonanterior lead location had significantly improved survival (P < 0.001). There was also a trend for improved survival in those with nonapical lead location (P = 0.09). CONCLUSION: In this case-matched two-centered study, comparable improvements were noted in patients with tLV-CRT and eLV-CRT. Operators should target nonanterior and nonapical locations during eLV-CRT implantation. Use of eLV-CRT should be considered a viable alternative for CRT candidates.

Lead extractions: indications, procedural aspects, and outcomes.

As a result of more cardiac implantable electronic devices being placed, a trend toward increasing device infections, and concerns regarding lead malfunction, there is an increased need for lead extraction skills and comprehensive lead management programs. This review discusses the current indications for lead extractions as well as the training requirements and tools and technology needed to create the foundation for a successful lead management program.

Pocket infections of cardiac implantable electronic devices treated by negative pressure wound therapy.

AIMS: Managing an infection of the pocket of a cardiac implantable electronic device (CIED) is frequently challenging. The wound is often treated with a drain or wet-to-dry dressings that allow healing by secondary intention. Such treatment can prolong the hospital stay and can frequently result in a disfiguring scar. Negative pressure wound therapy (NPWT) has been frequently used to promote the healing of chronic or infected surgical wounds. Here we describe the first series of 28 patients in which NPWT was successfully used to treat CIED pocket infections. METHODS AND RESULTS: After removal of the CIED and debridement of the pocket, a negative pressure of 125 mmHg continuously applied to the wound through an occlusive dressing. Negative pressure wound therapy was continued for a median of 5 days (range 2-15 days) and drained an average of 260 mL sero-sanguineous fluid (range 35-970 mL). At the conclusion of NPWT, delayed primary closure of the pocket was performed with 1-0 prolene mattress sutures. The median length of stay after CIED extraction was 11.0 days (range 2-43 days). Virtually all infected pockets healed without complications and without evidence of recurrent infection over a median follow-up of 49 days (range 10-752 days). One patient developed a recurrent infection when NPWT was discontinued prematurely and a new device was implanted at the infected site. CONCLUSION: We conclude that NPWT is a safe and effective means to promote healing of infected pockets with a low incidence of recurrent infection and a satisfactory cosmetic result.

Standard chest radiograph predicts left ventricular lead location in chronic resynchronization therapy patients more accurately than intraoperative fluoroscopy.

INTRODUCTION: Targeting the proper left ventricular lead site is important in cardiac resynchronization therapy (CRT) procedures, as suboptimal lead locations may result in a lack of clinical response. Left ventricular lead locations are typically confirmed using fluoroscopy (fluoro) with AP, RAO, and LAO orientations. However, standard fluoro may inadequately delineate true left ventricular lead locations, due to insufficient angulation or extreme cardiac rotation. Posteroanterior and lateral chest radiograph (CXRPAL), performed routinely to verify lead stability and freedom from complication, may better confirm left ventricular lead location due to utilization of a straight lateral view. HYPOTHESIS: Compared to fluoro, lead localization using CXRPAL will be more predictive of true left ventricular lead location in CRT patients. METHODS: Of 252 medically optimized CHF patients who underwent CRT implantation by multiple operators from October 2001 to August 2011, 46 (mean age, 58.9 ± 13.2 years; 10 female; 19 ICM; 19 LBBB; mean ejection fraction, 26.6 ± 8.9 %; mean QRS width, 144.4 ms) had CT scanning performed as part of routine medical care and comprise this study. Operative reports of left ventricular lead location by fluoro were reviewed. Left ventricular lead location was identified on CXRPAL by three independent observers blinded to operative results. Left ventricular lead locations according to fluoro and CXRPAL were correlated with CT scan at a mean follow-up of 57.6 ± 28.8 months (Tables 1 and 2). RESULTS: Compared to standard fluoro, CXRPAL agreed better with CT scan (κ = 0.413 fluoro vs. κ = 0.864 CXRPAL on the vertical axis, and κ = 0.086 fluoro vs. κ = 0.864 CXRPAL on the horizontal axis) for identification of left ventricular lead location. CONCLUSIONS: In this small study of 46 CRT patients, interpretation of left ventricular lead location using CXRPAL correlated better with true lead location identified on CT scan, compared to standard fluoroscopy. Use of a steep lateral view during CRT implantation may be necessary to accurately identify left ventricular lead locations.

Prognostic significance of atrial arrhythmias in a primary prevention ICD population.

INTRODUCTION: We investigated whether primary prevention implantable cardioverter defibrillator (ICD) patients with atrial arrhythmias are at higher risk for ICD shocks and mortality compared to patients without atrial arrhythmias in a subanalysis of the PREPARE study. METHODS AND RESULTS: Details of the PREPARE study design and results have been previously reported. We now included 537 of the 700 patients enrolled in PREPARE. These patients had a dual or biventricular device and at least one device follow-up after implantation. Continuously collected device diagnostics data were used to classify patients into two groups during follow-up: with (n = 133) or without (n = 404) atrial tachycardia/atrial fibrillation (AT/AF). The primary outcomes were ICD shocks and mortality. Subjects were followed for a mean of 333 ± 73 (range 5-365) days. During a follow-up of 1 year, ICD shocks occurred in 44 (8%) patients. Significantly, more patients with AT/AF received a shock (13.0% vs 6.9%, P = 0.03), with inappropriate shocks accounting for the majority of the difference (6.9% vs 2.6%, P = 0.02). There was no difference in prevalence of shocks between patients with and without a history of AF. Mortality was similar in patients with and without AT/AF, whether detected during the study or prior to the study. In addition, the 34 subjects with high average ventricular rate (≥110 beats per minute) during AT/AF had a higher risk of an inappropriate shock (21.0% vs 2.1%, P < 0.01). CONCLUSION: Primary prevention ICD patients with AT/AF are more likely to receive shocks, especially inappropriate shocks. Mortality was not higher in AT/AF patients. (PACE 2011; 34:1070-1079).

Strategic programming of detection and therapy parameters in implantable cardioverter-defibrillators reduces shocks in primary prevention patients: results from the PREPARE (Primary Prevention Parameters Evaluation) study.

OBJECTIVES: Our purpose was to demonstrate that strategically chosen implantable cardioverter-defibrillator (ICD) ventricular tachycardia (VT) or ventricular fibrillation (VF) detection and therapy parameters can reduce the combined incidence of device-delivered shocks, arrhythmic syncope, and untreated sustained symptomatic VT/VF (morbidity index). BACKGROUND: Strategically chosen ICD VT/VF detection and therapy parameters have been shown in previous studies to reduce the number of shocked episodes. In the PREPARE (Primary Prevention Parameters Evaluation) study, these prior strategies were combined with additional strategies specific to primary prevention patients. METHODS: The PREPARE study was a prospective, cohort-controlled study that analyzed 700 patients (biventricular [Bi-V] ICD and non-Bi-V ICD) with primary prevention indications for an ICD from 38 centers followed for 1 year. VT/VF was detected for rates > or =182 beats/min that were maintained for at least 30 of 40 beats. Antitachycardia pacing was programmed as the first therapy for regular rhythms with rates of 182 to 250 beats/min, and supraventricular tachycardia discriminators were used for rhythms < or =200 beats/min. The control cohort consisted of 689 primary prevention patients from the EMPIRIC (Comparison of Empiric to Physician-Tailored Programming of Implantable Cardioverter Defibrillators Trial) (non-Bi-V ICD, physician arm only) and MIRACLE ICD (Multicenter InSync Implantable Cardioversion Defibrillation Randomized Clinical Evaluation) (Bi-V ICD) trials for whom VT/VF detection and therapy programming were not controlled. RESULTS: The PREPARE programming significantly reduced the morbidity index incidence density (0.26 events/patient-year for PREPARE study patients vs. 0.69 control cohort, p = 0.003). The PREPARE study patients were less likely to receive a shock in the first year compared with control patients (9% vs. 17%, p < 0.01). The incidence of untreated VT and arrhythmic syncope was similar between the PREPARE study patients and the control cohort. CONCLUSIONS: Strategically chosen VT/VF detection and therapy parameters can safely reduce shocks and other morbidities associated with ICD therapy in patients receiving an ICD for primary prevention indications. (PREPARE-Primary Prevention Parameters Evaluation; NCT00279279).